1. Field of the Invention
The present invention relates to an information processing apparatus, method, and program, particularly to an information processing apparatus, method, and program for recognizing an object in an image.
2. Description of the Related Art
Recognition of an object present in an image, for example, captured by a camera, has been studied for a long time. The majority of such studies have been how to describe the object in perspective, that is, how to recognize the object by preparing a texture template for the entire object and applying the template to the entire object to check if the object matches the template. Such methods, however, have difficulty in recognizing an object in a captured image, for example, when part of the object is hidden or the image includes a complicated background.
To address such a problem, there has recently been proposed a method that is very robust to a partially hidden portion of an object, a complicated background and the like in a captured image by describing the object using a local feature value and carrying out matching between local feature values (for example, see D. G. Lowe, “Object Recognition from local scale—invariant features”, ICCV, 1999, hereinafter referred to as the non-patent document 1).
There have been proposed a large number of methods for recognizing a less-textured object by using the shape of the contour of the object, such as edges. The majority of the edge-based recognition methods also use perspective description, so that they have significant difficulty in extracting the contour of an entire object in a typical image. Further, as described above, the methods using perspective description have difficulty in recognizing an object when part of the object is hidden or the background is complicated.
To address such problems, there have recently been proposed methods for locally describing an edge based on the above-mentioned method for describing texture by using a local feature value (for example, see S. Belongie, J. Malik, and J. Puzicha, “Shape Matching and Object Recognition Using Shape Contexts”, PAMI, 2002, and F. Jurie and C. Schmid, “Scale—invariant shape features for recognition of object categories”, CVPR, 2004, hereinafter referred to as the non-patent documents 2 and 3).